Mesenchymal stem/stromal cells are not infected by SARS-CoV-2 and retain their immunomodulatory potential as published by Institute for Transfusion Medicine and Immunohaematology, German Red Cross Blood Donor Service in Frankfurt am Main on Stem Cells Report.

Previous studies reported safety and applicability of Mesenchymal Stem/Stromal Cells (MSC) to ameliorate pulmonary inflammation in ARDS. Thus, multiple clinical trials assessing the potential of MSC for COVID-19 treatment are underway. Yet, as SARS-inducing corona viruses infect stem/progenitor cells, it is unclear whether MSC could be infected by SARS-CoV-2 upon transplantation to COVID-19 patients.

This paper shows that MSC from bone marrow, amniotic fluid and adipose tissue carry angiotensin-converting enzyme 2 and transmembrane protease serine subtype 2 at low levels on the cell surface under steady state and inflammatory conditions. It was neither observed SARS-CoV-2 infection nor replication in MSC at steady state, under inflammatory conditions, or in direct contact with SARS-CoV-2 infected Caco-2 cells. Further, indoleamine 2,3-dioxygenase 1 production in MSC was not impaired in the presence of SARS-CoV-2.

In this paper it’s shown that MSC are resistant to SARS-CoV-2 infection and retain their immunomodulation potential supporting their potential applicability for COVID-19 treatment.